1. Field of the Invention
The invention relates to distribution of digital content.
2. Related Art
Distribution of digital content for media streams, such as for example movies, is subject to several problems. One problem is that it is easy to make exact copies of digital content, thus allowing any recipient of that content to redistribute it, whether or not authorized to do so. It would be advantageous to be able to distribute digital content, particularly digital content for media streams, without fear of its unauthorized distribution. This would be particularly advantageous when it is desired to distribute digital content using a communication link, such as for example a computer network or other technique for distribution to end viewers (for example, either on demand, in anticipation of future demand, or in response to something else).
One known solution is to mark digital content with a “fingerprint,” so that an unauthorized distributor of the content can be determined, thus hopefully deterring potential unauthorized distributors. However, fingerprinting of digital content is subject to several problems.
First, fingerprinting can require substantial computation and memory resources. If the fingerprint were to be embedded at a single point of origin, that point of origin would have to be scaled up in size and power commensurate with the number of movies and the number of end viewers requesting those movies.
Second, fingerprinting can require substantial amount of time to perform. If a media stream were to be distributed to end viewers starting at a selected release time, as is sometimes common for first-release movies, there would be a substantial delay in distribution at about the release time due to queuing of more requests for the media stream than could be handled in real-time.
Because of the relatively large amounts of data needed to be sent, it would be advantageous to distribute digital content for media streams in a tiered or cached system, that is, one in which the digital content is moved outward from a point of origin to devices that are closer to end viewers in terms of (1) cost for communication, (2) latency for sending and receiving messages, and other factors. However, conventional fingerprinting is substantially inconsistent with a system in which digital content is substantially distributed before the end viewer is known.